saw 2 very bright objects in western sky, one disappearing from view somehow (not sure where it went) the other object was huge, triangular, w/a few lights on the sides + middle. was flying very low and no sound

Driving home late one night last fall, my boyfriend and I were heading from the east side of Rockford to the west side. Immediately, we noticed 2 very bright lights in the western sky and they appeared to be flying quite low. I assumed they were helicopters because they were too low to be planes, plus they were not going very fast. Within a minute, we lost sight of one of the objects and it never did reappear. What happened to it, I do not know. The other object, however, was within view during our whole trip home. The farther west we drove, the larger this object began to appear. As we neared home, the object was nearly overhead and it seemed huge. It was triangular in shape. We were so concerned with what it was that we pulled over the car on a side street and got out to get a good look at it. We could not figure out what the hell it was! It was at least the size of a commercial airplane, but I believe it was possibly quite a bit bigger...it was hard to judge the actual size and distance away, but it was flying extremely low...I would estimate it was flying no higher than 1000-2000 feet above the ground. There were a few lights on the sides and one or two in the middle...cannot remember the color of these lights, but I believe they were white and possibly blue. The object produced absolutely NO SOUND WHATSOEVER. That was how we were certain that it was not a plane...unless it was some kind of military craft, but rarely do any military craft fly over Rockford, and even if they did, why would they do so at 1 am? This object was flying towards the south at a very slow but steady rate of speed, but then took an extremely sharp turn to the west, and we then lost track of it because trees were blocking our view from where we had gotten out of the car. This is something that has never happened to me and I felt very strange and edgy the rest of that night.